The difficulty with the proposed high-speed train line is that a used plane can be bought for one-third the price of the train line, and the plane, which is just as fast, can fly anywhere. The train would be a fixed linear system, and we live in a world that is spreading out in all directions and in which consumers choose the freewheel systems (cars, buses, aircraft), which do not have fixed routes. Thus a sufficient market for the train will not exist.

Which of the following, if true, most severely weakens the argument presented above?

• ACars, buses, and planes require the efforts of drivers and pilots to guide them, whereas the train will be guided mechanically.  
• BCars and buses are not nearly as fast as the high-speed train will be.  
• CPlanes are not a free-wheel system because they can fly only between airports, which are less convenient for consumers than the highspeed train's stations would be.  
• DThe high-speed train line cannot use currently underutilized train stations in large cities.  
• EFor long trips, most people prefer to fly rather than to take ground-level transportation.